1. Field of the Invention
The present invention relates to new and useful improvements in wire cutting apparatus for helicopters and more specifically, to cutting apparatus intermediate the rotor and the helicopter fuselage for cutting wires which may become engaged in this area before the wire causes a severe crash.
2. Description of the Prior Art
Present wire cutters on helicopters for protecting that area between the rotor and the fuselage consist of a fixed V-shaped cutter facing in the forward direction on the top of the helicopter fuselage in front of the rotor mast. Cutters of this type are effective when the wire struck by the helicopter is at a ninety degree angle to the path of travel of the helicopter. When this type of fixed V-shaped cutter strikes a wire at other than a ninety degree angle, the torque exerted on the cutter will cause it to collapse, rendering the cutter ineffective and resulting in a possible crash of the helicopter.
To provide effective protection to the helicopter, regardless of the direction of wire strike, cutting means vertically spanning the space between the fuselage and the rotor is provided which rotates with the rotor and which has cutting edges thereon adapted to engage and direct the wire toward the vertical midpoint of the cutter and cut the wire. This cutting means can be multiple cutting edges on the pitch control rods for the rotor blades extending lengthwise thereof and skewed relative to the longitudinal axis of each pitch control rod. Alternatively, if the pitch control rods do not span the entire space between the fuselage and rotor, a cylindrical drum may be provided surrounding the pitch control rods and carried by the rotor mast so that it rotates with the rotors. Cutting blades skewed in such a manner relative to the axis of the drum to drive any engaged wire toward the middle of the drum are mounted on the peripheral surface of the drum and serve to cut the engaged wire. The cutting blades on the drum preferably are arranged in a herringbone pattern with the ends of the blades adjacent the top and bottom of the drum being in advance of midportion of the blades in the direction of rotation of the drum.
From the above, it can be seen that the primary object of the present invention is to provide effective wire cutting means to protect a helicopter from a wire strike intermediate the rotor and the fuselage.
A further object of the present invention is to provide novel wire cutting means which will not add appreciably to the weight of the helicopter and may be installed quickly and efficiently.
Other objects will be apparent from the description of the invention.